Project Summary This project will enhance and develop the only source of data that provides core information about work, education, income, and migration for the entire U.S. population. This unique resource allows us to observe today's late-life population when they were young. This allows a prospective view of the impact of early-life environments and socioeconomic status on health and well-being in later life. The massive database describes the characteristics of all 133 million persons who resided in the United States in 1940. The data have been available for only a brief period, but are already having a profound impact on scientific research. They are the primary data source for at least 19 sponsored projects, including nine funded by NIH and seven funded by NSF. Through May 2017, 104 investigators had produced 95 papers based on the data, including 22 articles, four books, three PhD dissertations, and 66 working papers. This project will improve the quality and usability of the database by correcting transcription errors; improving the coding, editing, and allocation of key variables; and introducing new data dissemination tools designed to simplify access to the data. The project will undertake three major activities to meet these objectives. 1. Incorporate new verified census information on name, age, sex, family relationship, race, marital status, birthplace, and residence five years ago. 2. Improve coding, editing, and allocation for geographic variables, migration, occupation, and numerically- coded variables such as income. 3. Apply new technologies to democratize access to the data through new data access tools and a virtual data enclave for a restricted version of the data that contains names. This project is a highly cost-effective use of scarce resources to develop shared infrastructure for research, education, and policy-making on health and aging. The proposed improvement of data quality is urgent, and will provide a resource of unprecedented power for understanding the effects of public policies, social institutions, and environmental conditions on the health, well-being, and functioning of people, both over the life course and in their later years.